Related papers: Anomalous Spin Dynamics in Doped Quantum Antiferro…
Planar oxygen nuclear magnetic resonance (NMR) relaxation and shift data from all cuprate superconductors available in the literature are analyzed. They reveal a temperature independent pseudogap at the Fermi surface, which increases with…
Normal and superconducting state spectral properties of cuprates are theoretically described within the extended t-J model. The method is based on the equations of motion for projected fermionic operators and the mode-coupling approximation…
A spin-fermion model relevant for the description of cuprates ladders is studied in a path integral formalism, where, after integrating out the fermions, an effective action for the spins in term of a Fermi-determinant results. The…
We present $^{75}$As Nuclear Magnetic and Quadrupole Resonance results (NMR, NQR) on a new set of LaFeAsO$_{1-x}$F$_x$ polycrystalline samples. Improved synthesis conditions led to more homogenized samples with better control of the…
In an attempt to explain inelastic neutron scattering data for LiV2O4 the dynamical spin susceptibility \chi(Q,w) at zero temperature is calculated. Starting point is a weak coupling approach based on the LDA bandstructure for that…
$^{31}$P nuclear magnetic resonance (NMR) measurements have been carried out to investigate the magnetic properties and spin dynamics of Fe$^{3+}$ ($S$ = 5/2) spins in the two-dimensional triangular lattice (TL) compound…
The translational-diffusion coefficient $D_T$ and the spin-rotation contribution to the $^1$H NMR relaxation time $T_{1J}$ for methane (CH$_4$) are investigated using MD (molecular dynamics) simulations, over a wide range of densities…
We present muon spin lattice relaxation measurements in the V15 spin 1/2 molecular nano-magnet. We find that the relaxation rate in low magnetic fields (<5 kG) is temperature independent below ~10 K, implying that the molecular spin is…
We report the NQR study on the pressure-induced paramagnetic state in the antiferromagnetic (AF) intermetallic compound YMn$_2$ with the N\'eel temperature T_N=100 K at ambient pressure. From the $T$ variation of the nuclear spin-lattice…
We use the density matrix renormalization group method (DMRG) to compute the frequency and momentum resolved spin-spin correlation functions of a dimerized spin-1/2 chain under a magnetic field at finite temperature. The spectral features…
We determine the phase diagram of LaFe$_{1-x}$Co$_x$AsO single crystals by using nuclear magnetic resonance (NMR). Up to a nominal doping of $x=0.03$, it follows the phase diagram for F-doped polycrystals. Above $x=0.03$, the F-doped…
In this communication we consider the doping dependence of the strong antiferromagnetic spin fluctuations in the cuprate superconductors. We investigate the effect of an incommensurate magnetic response, as recently observed in inelastic…
We present a relativistic spin-fermion model for the cuprates, in which both the charge and spin degrees of freedom are treated dynamically. The spin-charge coupling parameter is associated with the doping fraction. The model is able to…
We determine the magnetic phase diagram for the YBa$_2$Cu$_3$O$_{6+x}$ and La$_{2-x}$Sr$_x$CuO$_4$ systems from various NMR experiments. We discuss the possible interpretation of NMR and neutron scattering experiments in these systems in…
The excitations of the Heisenberg antiferromagnetic spin chain in zero field are known as spinons. As pairwise-created fractionalized excitations, spinons are important in the understanding of inelastic neutron scattering experiments in…
We explain recently observed linear temperature dependence of the nodal Fermi velocity $v_F (T)$ in near-optimally doped cuprates. We argue that it originates from electron-electron interaction, and is a fundamental property of an arbitrary…
The spin structure in a magnetic dot, which is an example of a quantum few-body system, is studied as a function of exchange coupling strength and dot size with in the semiclassical approximation on a discrete lattice. As the exchange…
A comprehensive comparison between the magnetic field- and temperature-dependent low frequency spin dynamics in the antiferromagnetic spin-1/2 Heisenberg chain (AFHC) system copper pyrazine dinitrate, probed via the 13C-nuclear magnetic…
Spin-dynamics techniques have been used to perform large-scale simulations of the dynamic behavior of the classical Heisenberg antiferromagnet in simple cubic lattices with linear sizes $L\leq 60$. This system is widely recognized as an…
Using the modified spin-wave theory we calculate static and dynamic spin structure factors in spin-liquid state of the J1-J2 model. The spectrum of excitations in the vector channel is discussed. The developed technique can also be applied…